Common sources of invalid JSON
- - Trailing commas, single-quoted strings, and unquoted keys often come from JavaScript, Python, or hand-edited snippets.
- - Copied log output and chat messages frequently mix in extra text, comments, or incomplete structures.
- - Values such as `None`, `undefined`, `NaN`, or incorrectly cased booleans are not valid JSON.
Recommended repair workflow
- - Start with JSON Repair to normalize the obvious syntax problems.
- - Use JSON Validator next when you need precise error confirmation and locations.
- - Continue with JSONPath Tester or JSON Diff if you need to inspect paths or compare repaired output.